2.5mm Male to 3.5mm Female Audio Adapter Premium Quality Converter Headphone Earphone Headset 3 Ring Jack - Stereo or Mono

The MIDI ins and outs on the UNO are (for some unknown reason, maybe they saved a penny on each in manufacturing?!?!) 2.5mm.These converters turn those jacks into 3.5mm, which means you can use "regular" mini jack-to-MIDI jump cables. Sure you get a pair of the right cables with your UNO, but it's always safer to have 1) spares and 2) more universality whenever possible, IMO.I make my own MIDI jumper cables, because I never know whether I need a type A or a type B for a given project, but FWIW the ones that work with Korg products (SQ1, SQ64, etc - the Volcas have man-sized MIDI DIN) are the ones that work with the UNO. One of these days I'll put a polarity switch on all my cables to I have both bases covered, but I digress.Get a pair and chuck 'em in your pack.

UPDATE: Initially I thought this would work to convert the headset 3.5mm so I could use it on my 2.5mm home phone plug. The dial tone is very clear but only comes through the right ear. Unfortunately that is where it stops as I found out the person on the other side of the line cannot hear you. I tried several times to adjust the connection between the 2.5mm and 3.5mm and you can make it work but the feedback squeals loudly and as such, will not work for what I needed it to do. Just a note -- this will NOT work as a conversion to phones.I purchased this to use with a 3.5mm headset recently purchased. Fully connected I only have sound out of the right side of the headset (which is typical for many wired telephone headsets) but it serves the purpose of what I needed.

When I plug this in all the way I can only hear with one ear and I cant be heard at all by the other person when talking. If I pull it out a bit It works normally but if I move the wrong way (Because it is not stable Since it isn't inserted all the way in) It doesn't work unless i sit still and not move to mess up the connection. I have ordered a 2.5 headset instead of trying to use an adapter to try and save money.

It works just fine with my Audio Technica M40X, but I was disappointed when only one came in the package when there was supposed to be two. I didn’t need a second one because I was only modding one headset, but this needs to be addressed.

Photo connected with the item shows two adapters. When my order arrived, I had one. Does it work? Sound quality is not great but it's unclear whether the problem is with this adapter or the cassette player I'm using it on.

Works great

I own a pair of Drop+Epos PC38X and they use a 2.5mm-to-3.5mm cable for input. I own other cans that use just 3.5mm so I ordered this adapter to keep in the PC38X so I wouldn't have to switch entire cables running into my DAC/Amp.. and it works great! The adapter sticks out just enough from the headphones to make it easy to plug in my 3.5mm cable. The entire adapter will pull out with the cable when disconnecting it.. so you'll either have to plug the adapter back in or just get good at holding the adapter in place with your thumb as you pull lol. To me, that's a minor inconvenience than having to switch out a whole other cable.

It allows my child to use Earbuds when using Xbox360 to stream movies or play a game. I am Sooo glad Microsoft went to 3.5mm Jack for Xbox One X or all Xbox Ones and I think it will be standard on New Series X coming out soon. One of best small feature change for Xbox so you can just plug in any headset and go Gaming & Chat. If there were some advantage for 2.5mm to use Microsoft Super Duper headphones or such it would have made sense but nope. TY Microsoft, as that is another little thing that could push people to PS4 instead of Xbox. I prefer (love) the Xbox One X in white as it looks classy and like a piece of furniture with clean look and if room is painted white or most light collors you can mount it on wall or inside entertainment center on its side & it matches so it does not pickup heat from other devices like next to my Bedroom Plasma 46" it that heats the whole F#@ing bedroom.